Cycles are one of the most widespread and efficient forms of individual human transport. The genesis of cycling produced the ‘Penny Farthing’ cycle with an oversized front wheel and a small stabilizing rear wheel. The Penny Farthing displayed numerous drawbacks of this design, including speed/efficiency limitations from a direct drive front wheel, difficulties in mounting/dismounting and limited manoeuvrability. These drawbacks brought about the diamond frame, chain driven rear wheel cycle configuration well-established to this day. Although significant developments have occurred in materials and ancillary equipment such as brakes, suspension and gears, this basic cycle configuration has evolved little over the subsequent 120 years.
Contemporary cycle design has been largely influenced by off-road riding or street/track racing and the corresponding cycle design elements heavily influence the consumer products marketed by cycle manufacturers. Despite the bias to designs optimised for such sporting origins, the overwhelming majority of cycles are used in non-competitive applications in urban environments for commuting and general transport. Cycles optimised for urban use have also been produced, though these tend to be adaptations of mountain bike designs with road-orientated tires, simplified or no suspension and a more upright seating position than racing/sport orientated cycles. They can also suffer from a social perception of being staid, old-fashioned and lacking the intangible vicarious credibility of association with more dynamic sporting/adventurous activities.
However, increasing urban congestion, inexorable fuel cost increases and the predominance of workplaces being located in cities has created significant interest in alternatives to motor vehicle transportation. Public transport should present an attractive solution to many of these shortcomings in urban motor vehicle transport, particularly in commuting. However, much to the frustration of civil authorities, there is significant reluctance amongst individual travellers to lose the freedom of movement offered by individual transport. This reluctance is so well ingrained in many individuals that they will tolerate extensive traffic congestions, prolonged journey times as well as inconvenient and/or expensive parking options to maintain that perceived freedom.
Cycling offers a very attractive alternative for urban transport, and results in negligible traffic jams, zero fuel costs, minimal maintenance overheads and environmental impact. However, a significant number of potential users are still deterred from urban cycle usage by considerations including;                1. impracticability for extended commuting distances without supplementing with public transport;        2. incompatibility with most forms of public transport;        3. storage and/or security issues when not being ridden and/or being carried on public transport;        4. inconvenience of combining with automobiles for multi-mode journeys,        5. physical effort required for un-assisted pedal cycle travel.        
A combination of cycle travel and either public transport or private vehicles offers a potential synergy of the beneficial attributes of both transport modes, namely;                users retain the freedom of movement at either end of their journey, while a bus, train, tram, car or the like provides rapid distance coverage in-between, and;        both conveyance means are cost-effective, with low per-person environmental impact compared to car travel.        
Further benefits include the increased effectiveness of inner-city living, providing freedom of movement without the cumbersome coupling to public transport routes and timetables.
Unfortunately, cycles are also unwieldy, cumbersome objects to stow, carry or generally manipulate when not being ridden. Moreover, the majority of public transport is designed for ambulant individuals with minimal hand luggage of an essentially stowable/portable nature. Cycles cause significant handling difficulties for users during ingression/egression of buses, trains, or trams, they may obstruct doorways/passageways, hinder other passengers and possible cause minor impact injuries and/or clothing soiling from contact with the numerous inflexible projections, chains and the like. Many public forms of transport cannot accommodate conventional cycles, motor scooters or motor bikes at all, or they must be placed in special freight compartments.
Although occupying far less volume than motor vehicles, conventional cycles pose security issues for travellers when not in use. A variety of locks, chains, and the like are routinely used by cyclists to prevent theft. Unfortunately, the very adaptability and simplicity of cycles, vis-à-vis adjustable, quick release fitting/accessories (e.g. seats, wheels, lights, panniers, trip computers and so forth) often requires the rider to partially dismantle the cycle, secure each fitting and/or completely detach the items from the secured cycle secured to a rack, post or similar. Clearly, commonplace procedures such as having to detach the front wheel and place adjacent the rear wheel to enable a security chain/lock to pass through both wheels and having to carry a cycle seat, lights or the like is far from convenient or desirable. The alternative however, of taking a conventional cycle into a typical office building and negotiate stairwells, lifts, narrow corridors, or office cubicles is also fraught with difficulties.
The physical effort of cycling creates further disincentives to those with employment in professional offices, customer service, or any environment requiring good personal presentation. The attendant overheads of additional showering and/or clothing changes to maintain acceptable workplace personal presentation and hygiene is often perceived as too inconvenient to warrant the effort in cycle commuting. Electric cycles and pedal-assisted electric cycles have been developed to supplement the rider's leg power. In general, the addition of an electrical drive mechanism adds significantly to the cost and weight of the cycle without in itself addressing the first three deterrents to urban cycling usage listed above.
Unsurprisingly therefore, there have been regular and concerted attempts to produce a practical folding, collapsible or otherwise compactable cycle to ameliorate the above difficulties.
An inherent complication with creating a practicable folding system for conventional bicycle frame design include the numerous protrusions, the lack of stability in most orientations, and the desire to avoid dismantling the drive mechanism (particularly oiled chain drives) during collapsing/erecting. That collapsing cycles have become increasingly popular despite these drawbacks is testament to the greater problems faced by the alternative urban transport options and the overriding premium on space in urban environments ranging from congested roads, limited parking, personal workspaces and urban homes. There is thus a clear benefit in producing a compact bicycle capable of providing urban transport that may also be readily transported and stored by an individual when not being ridden.
Several factors have however hindered the widespread public acceptance of prior art collapsible cycles, namely:                compromised performance from typical design features including small diameter wheels, lack of frame rigidity;        unwieldy size, weight and resultant collapsed configuration of ‘full’-sized folding bike frames and wheel assemblies;        risk of entrapment and/or clothing soiling from a chain, gearing, brakes mechanism.        
Existing folding cycles may be classified according to their wheel diameter into three broad categories:                1. Full size cycles with comparable wheel diameters to conventional road cycles (i.e. 26″) often with a single frame hinge folding the cycle in half. The almost unrestricted on-road performance comes at the cost of minimal, if any reduction in volume of the collapsed cycle and additional cost.        2. Smaller (24-16″ diameter) wheels with more elaborate folding mechanisms. Typically 20″ diameter wheels are considered the threshold for effectively negotiating urban riding hazards such as curbs, speed bumps, pot-holes and the like.        3. Sub 16″ diameter wheels which place a premium on the collapsed volume over on-road performance. Often involving complex collapsing mechanisms, these cycles are generally difficult to ride for extended distances, or at speed and generally result in highly compromised riding functions, efficiencies and comfort.        
The target market for these three cycle types respectively spans:                intermittent recreational users who are happy to compromise ease and speed of foldability for enhanced riding performance and comfort;        urban commuters travelling regularly and for an appreciable distance, possibly mixed mode commuting in conjunction with public transport;        users with space premium environments (e.g., apartment dwellers, car drivers), possibly intermittent usage needs, short distances and high need for portability, mixed mode commuting, marine craft and the like.        
Self evidently, the largest potential market lies with regular urban commuters who need both cycle performance and effective folding, typified by purchases in the second category above. Typical purpose-designed collapsible bicycles in this category incorporate a hinged frame enabling the two halves of the frame to be folded together such that the two wheels lie substantially adjacent. Further folding techniques often include folding pedals, a hinged/detachable seat and the like. The resultant folded cycle is invariably still a large object with numerous projections and mechanisms which may become entangled with a user or external objects. Moreover, the wheel diameter provides a fundamental limitation on the degree of compaction possible without somehow dismantling the wheel itself.
Some of the features desirable in an idealised urban cycle include:                capacity for sustained super-walking speeds, notwithstanding a typically minimal need for high speeds (e.g. exceeding 20-30 km/h) in urban environments;        collapsible configuration and dimensions sufficiently compact and wieldy to be carried as a practical day-pack, bag or satchel;        minimal projections or protrusions in its collapsed state;        minimised maintenance requirements;        sufficient diameter wheels for riding comfort and the capacity to surmount routinely encountered urban obstacles such as curbs and potholes;        prominent, high-visibility, rider seating position;        high manoeuvrability, particularly at low speeds;        sufficient stability to be ridden by riders of low/average physical dexterity;        safe stopping means;        rapidly compactable without tools;        light-weight.        
Modern cycle design (including folding cycles) have largely settled on the well established configuration of front wheel steering, rear wheel chain drive (via a chain driven offset crank located between the wheels) with the rider positioned between two identically sized wheels with handlebar steering attached to the front wheel at approximately midriff height. Most powered cycles and motor cycles also adopt the same general configuration. This configuration is however incompatible with many of the above desirable characteristics for a folding cycle. Typical folding cycles retain both wheels attached to a frame which folds approximately in half about a substantially central hinge point. Consequently, usage of small diameters for both wheels is commonly employed to reduce the folded cycle volume, with the resultant drawbacks discussed above.
Moreover, for pedal driven cycles, achieving a worthwhile degree of compaction from a reduced wheel size creates an impractically small pedal crank length for ergonomically efficient usage or requires the use of a conventional chain drive with the pedal crank exterior from the wheel. In the latter configurations, the use of cranks sized for efficient adult human usage necessitates positioning the pedal shaft in a higher horizontal plane than the rotational axis of the driven wheel to avoid ground contact during pedalling.
The presence of an exposed chain further reduces the practicality of carrying a collapsed cycle as a backpack or satchel without the risk of soiling the user's clothing. The complications associated with detaching and re-attaching a chain from a wheel precludes such actions as a practical and convenient step to overcome such drawbacks.
Shortening the wheelbase of a cycle can reduce its folded size. However, the reduced stability due to the riders high centre of gravity increase the vulnerability of overturning during braking or when striking an obstruction. The risks associated with a rider pitching forward are exacerbated by the conventional placement of the handlebars in front of the rider and above their knees causing the rider to strike the handlebars or become entangled in the machine, trapped by the handlebars.
The infancy of bicycle design explored a variety of configurations including the ‘penny farthing’ configuration; —asymmetrical wheel size, direct pedal crank drive (i.e. no chain and gearing), and a very large front wheel diameter. However, one of the difficulties with direct front-wheel-drive, front-wheel-steer pedal cycles of this type, particularly when starting from rest, is that pressure applied to the pedals exerts a destabilising steering effect. Driving the pedal crankshaft about the center of the front wheel also imposes ergonomic constraints on:                the type of frame configurations;        possible seating positions;        the maximum pedal crank size possible without risk of grounding, and        the maximum and minimum wheel diameter.        
Powered cycles may use auxiliary power units to supplement pedal power (e.g. when travelling up inclines) or be powered solely by a power unit such as a combustion engine or electrical drive. Prior art powered cycles suffer from the aforesaid drawback of pedal cycles plus the additional complexity, cost and weight associated with incorporating the power unit into a collapsible cycle configuration. It will be thus appreciated there is a need for a compactable cycle with at least some of the aforementioned desirable features, while mitigating at least some of the disadvantages outlined. It would be particularly advantageous to provide such a bicycle which is also readily collapsible into a compact package for storage or transport.
Document DE 28 04 993 A1 by Ampaglas discloses a cycle according to the preamble of claim 1.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.